Expansion Joints Rubber


Rubber-made COFLEX® expansion joints represent the most widely items used in the industry, although their ideal use is on piping connected on one side to a moving part and on the other side to a fixed one.

COFLEX® joints, thank to their composite structure consisting of an inner and outer rubber with a fabric reinforcement, (synthetic or metallic), depending on their geometrical profile, allow more or less wide displacements with a relative rigidity of the three axis.

COFLEX® expansion joints rubber made divide into very elastic types, (provided with very good vibration proof/structural noise features) and harder types yet very suitable also for critical uses.

They are particularly used for:

·        Connecting pumps to suction/discharge ducts

·        Connecting duct sections undergoing thermal expansion

·        Connecting buried ducts undergoing settlement movements

·        Connecting motors to base and related ducts, for ships and industry.

Further information about the features differencing the two types of joint, you are kindly requested to refer to the report worked out by COFI, just to be of help to the customers in choosing the most suitable COFLEX® expansion joints, as to elasticity and related capability to cut vibrations.

Rubber COFLEX® expansion joints are made in a very wide range, starting from DN 20 to DN 3500 and over.

COFI s.r.l., has asked and obtained the type approval from several shipping registers for different expansion joints, which have recently obtained the MED type approval according to the Directive 96/98/EC, of which we list including the relevant certificates (downloadable by clicking on them):



  • COFLEX®D2 - D2CF 


Below, some executions are pointed out, and manufactured following the technical standards for use on ships, such as:

·        COFLEX® expansion joints according to the Navy standard of MMI

·        COFLEX® expansion joints according to MED standard, Directive 96/98/EC

·        COFLEX® expansion joints according to RINA standards, Lloyd’s Register of Shipping, Det Norske Veritas, Germanisher Lloyd, Bureau Veritas.

The following basic information are required for COFI Engineering Dep’t be able to work out design the correct way:

  • System design /operating Temperature
  • System design /operating pressure
  • Fluid type and its chemical aggressivity
  • Extent and direction of the movements to compensate
  • Frequency of movements
  • Fluid speed
  • Fluid’s solid contents
  • Special requirements or compliance with reference standards
  • Need for tests or type approvals
  • Auxiliary equipment material such as flanges, splitted counterflanges …
  • Possible fire hazard

Basing on the information obtained, Cofi’s technical dep’t will recommend either a standard joint already included in its wide range of products, or will recommend a made-to-size joint, by checking its actual operating features.


·        Long life time 

·        Strong vibration adsorption

·        High flexibility

·        Three-axes X-Y-Z movement

·        High cut of noise transmission

·        Use up to temperatures with peaks of 120°C, depending on material

·        Reaction stress reduced (no stress with self-stable joints COFLEX®K)

·        Minimum overall dimensions

·        A wide assortment of materials suitable for any kind of use.

·        Possible use of auxiliary equipment such as flanges, tie rods, bolts and nuts, made of the most different materials (from stainless steel to bronze including the most sophisticated plastic materials).

·        Easy maintenance operations.

 For further information and analysis, please refer to Cofi’s Technical Dep’t.

To get a sight of the Cofi products as well as more detailed information of the products range, please refer to the catalogues.